VDM Alloy 926 Cronifer 1925 hMo - VDM Metals | Home · PDF fileEN 1.4529 X1 NiCrMoCuN25-20-7...

VDM® Alloy 926

Cronifer 1925 hMo

Material Data Sheet No. 5102

September 2017

September 2017 VDM® Alloy 926 2

VDM® Alloy 926 is an austenitic, special stainless steel that was developed by VDM Metals on the basis of the many times

proven VDM® Alloy 904 L (1.4539). Due to its 6.5 % higher molybdenum concentration, VDM® Alloy 926 has a generally

improved corrosion resistance and resistance against pitting corrosion and crevice corrosion compared to VDM® Alloy

904 L. This also has a positive effect on the resistance against stress corrosion that is induced by pitting corrosion.

VDM® Alloy 926 is characterized by:

very good resistance against chloride-induced stress corrosion,

increased resistance against stress corrosion in comparison to other austenitic stainless steels,

excellent general corrosion resistance when in contact with oxidizing and reducing media,

higher strength than VDM® Alloy 904 L (1.4539),

low propensity to form inter-metallic phases,

Approval for pressure vessels in the temperature range from -196 to 400 °C (-272.2 to 752 °F).

Approval from building supervisory authorities for components and joining elements made of stainless steels,

Deutsches Institut für Bautechnik [German Centre of Competence for Construction], September ’98

Designations

Standard Material designation

EN 1.4529 X1 NiCrMoCuN25-20-7

UNS N08926

Standards

Product form DIN VdTÜV ASTM ASME EN Others

Sheet EN10088-2

EN10028-7

502 A 240

Strip EN 10028

EN 10088-2

A 240

B 625

SA 240

SB 625

API 5LD

Bar EN10088-3 502

502

B 649 SB 649 10222 NACE

0175/ISO15156

Wire EN 10088-2

Table 1 – Designations and standards

VDM® Alloy 926 Cronifer 1925 hMo


Chemical composition

C S N Cr Ni Mn Si Mo Cu P

Min. 0.15 20.0 24.0 6.0 0.5

Max. 0.02 0.010 0.25 21.0 26.0 1.0 0.5 7.0 1.5 0.03

Overall analysis corresponds to VdTÜV sheet 502

Due to technical reasons the alloy may contain additional elements

Table 2 – Chemical composition (%)

Physical properties

Density Melting range Relative magnetic permeability at 20 °C (68 °F)

8.1 g/m³ bei 20 °C

506 lb/ft3 at 68 °F

1,320 - 1,390 °C

(2,408 - 2,534 °F)

1.001

Temperature Specific heat capacity Thermal conductivity Electrical

resistivity

Modulus of elasticity Coefficient of thermal ex-

pansion

°C °F J

Kg · K

Btu

lb ∙ °F

W

m ∙ K

Btu ∙ in

sq. ft ∙ h ∙ °F

μΩ · cm GPa 106 psi 10-6

K

10-6

°F

20 68 415 0.0991 12.0 6.93 96 193 28.0 - -

100 212 435 0.104 12.9 7.45 99 186 27.0 15.0 8.33

200 392 470 0.112 14.4 8.32 104 179 26.0 15.7 8.72

300 572 495 0.118 16.5 9.53 108 173 25.1 16.1 8.94

400 752 510 0.122 18.5 10.7 112 168 24.0 16.4 9.11

Table 3 – Typical physical properties at room- and elevated temperatures


Microstructural properties

VDM® Alloy 926 has a cubic, face-centered crystal structure.

Mechanical properties

The following properties at room and elevated temperatures apply to VDM® Alloy 926 in the solution-annealed condition

and for the specified dimensions. The properties for larger dimensions must be agreed separately. The values are valid

for longitudinal and traverse test samples.

Temperature Yield strength

Rp 0.2

Yield strength

Rp 1.0

°C °F MPa ksi MPa ksi

20 68 300 43.5 340 49.3

100 212 230 33.4 270 39.2

200 392 190 27.6 225 32.6

300 572 170 24.7 205 29.7

400 752 160 23.2 190 27.6

500 932 120 17.4 150 21.8

550 1022 105 15.2 135 19.6

Table 4 – Mechanical properties at elevated temperatures, min. values according to VdTÜV material data sheet 502

Product

form

Dimensions Yield stress

Rp 0,2

Yield stress

Rp 1,0

Tensile strength

Rm

Elongation

at fracture1)

A

mm in MPa ksi MPa ksi MPa ksi %

Sheet ≤ 50 ≤ 1.97 ≥ 300 ≥ 43.5 ≥ 340 ≥ 49.3 600 – 800 87-116 ≥ 40

Strip ≤ 3 ≤ 1.18 ≥ 300 ≥ 43.5 ≥ 340 ≥ 49.3 600 – 800 87-116 ≥ 40

ar ≤ 300 ≤ 11.8 ≥ 300 ≥ 43.5 ≥ 340 ≥ 49.3 600 – 800 87-116 ≥ 40

1) Elongation at fracture: for flat products < 3mm (0.01 in) with lengthwise minimum values reduced by 5% - points

Table 5 – Mechanical properties at room temperature

ISO – V notch impact toughness

Temperature Notched-bar impact strength (J/cm²)

-196 °C (-321 °F) ≥125

20 °C (68 °F) ≥150

Table 6 – The results of the notched-bar impact-bending test at the V-trial according to DIN EN ISO 148 -1 minimum average value of three trials (min. single value must not be less than 105 J/cm² at 20°C resp. 88 J/cm² at -196 °C).


Corrosion resistance

VDM® Alloy 926 is an austenitic, special stainless steel with largely the same chemical composition as VDM® Alloy 904 L,

while the nitrogen content was raised to 0.2 % and the molybdenum concentration to about 6.5 %. At the same time, the

resistance against stress crack corrosion induced by pitting corrosion is improved. The nitrogen concentration raised to

rounded 0.2 % improve the austenite stability and lowers the propensity to form inter-metallic phases. VDM® Alloy 926 is

a good pick for media such as diluted sulfuric and phosphorus acids that are contaminated with chlorides, and also for

salt concentrations and crystallizations against which the material proves a higher resistance against wear and tear. Due

to its good corrosion resistance in seawater, VDM® Alloy 926 is also used for facilities on offshore platforms. The optimal

corrosion behavior is only given if the material is used in clean, passivated condition.

Fig. 1 – Critical pitting corrosion temperature in 10 % FeCI3 x6H2O solution as a function of the effective sum in com-parison to some stainless steels and nickel alloys.

Fig. 2 – Time-temperature sensitization diagram (ZTS) of VDM® Alloy 926


Applications

Typical applications for VDM® Alloy 926 are:

Vaporizers, heat exchangers, tank housings, etc. in phosphorus acid production

Facilities and pipework in the use of diluted sulfuric and phosphorus acid, even if these are contaminated with

chlorides

Distributor systems and coolers for sulfuric acid plants

Concentration and crystallization plants in salt extraction by vaporization

Fire extinguishing systems, sea water filtration, hydraulics and injection systems of off-shore engineering

Pump frames of oil extraction pumps

Pump lines and couplings, wire lines in oil and gas extraction

Condenser pipes and pipework systems in power plants with heavily contaminated cooling water

Parts for flue gas desulfurization that are exposed to modest corrosion strain

Facilities and parts for the bleaching phase of the pulp industry

Flexible pipes in the off-shore industry

Tanks for storing and transport of aggressive chemical substances


Fabrication and heat treatment

VDM® Alloy 926 is ideally suited for processing by means of common industrial processing techniques.

Heating

It is important that the workpieces are clean and free of any contaminations before and during heat treatment. Sulfur,

phosphorus, lead and other low-melting point metals can result in material damage during the heat treatment. This type

of contamination is also contained in marking and temperature-indicating paints or pens, and also in lubricating grease,

oils, fuels and similar materials. The sulfur content of fuels must be as low as possible. Natural gas should contain less

than 0.1 wt.-% of sulfur. Heating oil with a maximum sulfur content of 0.5 wt.-% is also suitable. Electric furnaces are

preferable for their precise temperature control and a lack of contaminations from fuels. The furnace temperature should

be set between neutral and slightly oxidizing and it should not change between oxidizing and reducing. The workpieces

must not come in direct contact with flames.

Hot forming

VDM® Alloy 926 can be hot-formed in a temperature range between 1,200 and 900 °C (2,192 and 1,652 °F) with subse-

quent rapid cooling down in water or air. For heating up, workpieces should be placed in a furnace that is already heated

up to 1,200 °C (2,192 °F). Heat treatment after hot forming is recommended for achieving optimal corrosion behavior.

Cold forming

The workpieces should be in the annealed condition for cold forming. Due to its high molybdenum concentration, VDM®

Alloy 926 has a higher work hardening rate than other austenitic stainless steels. This must be taken into account for the

design and selection of forming tools and equipment and during the planning of forming processes. Intermediate annealing

is necessary for major cold forming work. For cold forming above 15%, a final solution annealing must be conducted.

Heat treatment

Solution annealing should take place at temperatures between 1,150 to -1,200 °C (2,102 to -2,192 °F) and preferably at

1,180 °C (2,156 °F). The retention time during annealing depends on the semi-finished product thickness and can be

calculated as follows:

For thicknesses of d <= 10 mm (0.39 in), the retention time is t = d ∙ 3 min / mm

For thicknesses of d = 10 to 20 mm (0.39 in to 0.79 in), the retention time t = 30 min + (d – 10 mm) ∙ 2 min/mm

For thicknesses of d > 20 mm (0.79 in), the retention time t = 50 min + (d – 20 mm) ∙ 1 min / mm

The retention time starts with material temperature equalization; longer times are generally considerably less critical than

retention times that are too short. Cooling down should be accelerated with water to achieve optimum properties. Fast air

cooling can also be carried out at thicknesses of less than approx. 1.5 mm. The material must be placed in a furnace that

has been heated up to the maximum annealing temperature before any heat treatment. For strips as the product form,

the heat treatment can be performed in a continuous furnace at a speed and temperature that is adapted to the strip

thickness.

Descaling and pickling

Oxides of VDM® Alloy 926 and heat tint in the area around welds adhere more strongly than in stainless steels. Grinding

using extremely fine abrasive belts or grinding discs is recommended. It is imperative that grinding burns be avoided.

Before pickling in nitric-hydrofluoric acid mixtures, the oxide layers should be destroyed by abrasive blasting or fine grind-

ing, or pre-treated in salt baths. The pickling baths used should be carefully monitored with regard to concentration and

temperature.


Machining

VDM® Alloy 926 is preferably processed in annealed condition. Since the alloy is prone to work hardening, a low cutting

speed should be selected with a feed speed that is not too high and the cutting tool should stay engaged at all times. An

adequate chip depth is important in order to cut below the previously formed work-hardened zone. An optimal heat dissi-

pation by using large quantities of suitable, preferably aqueous, cold forming lubricants has considerable influence on a

stable machining process.

Welding information

When welding nickel alloys and special stainless steels, the following information should be taken into account:

Safety

The generally applicable safety recommendations, especially for avoiding dust and smoke exposure must be observed.

Workplace

A separately located workplace, which is specifically separated from areas in which C steel is being processed, must be

provided. Maximum cleanliness is required, and drafts should be avoided during gas-shielded welding.

Auxiliary equipment and clothing

Clean fine leather gloves and clean working clothes must be used.

Tools and machines

Tools that have been used for other materials may not be used for nickel alloys and stainless steels. Only stainless steel

brushes may be used. Machines such as shears, punches or rollers must be fitted (e.g. with felt, cardboard, films) so that

the workpiece surfaces cannot be damaged by such equipment due to pressed-in iron particles as this can lead to corro-

sion.

Edge preparation

Edge preparation should preferably be carried out using mechanical methods such as lathing, milling or planing. Abrasive

waterjet cutting or plasma cutting is also possible. In case of the latter, however, the cut edge (seam flank) must be

reworked cleanly. Careful grinding without overheating is also permissible.

Striking the arc

Striking the arc may only take place in the seam area, e.g. on the seam flanks or on an outlet piece, and not on the

component surface. Scaling areas are places that may be more susceptible to corrosion.

Included angle

Compared to C-steels, nickel alloys and special stainless steels exhibit lower thermal conductivity and greater heat ex-

pansion. Larger root openings and web spacing 1-3 mm (0.04 in to 0.12 in) are required to live up to these properties.

Due to the viscosity of the welding material (compared to standard austenites) and the tendency to shrink, included angles

of 60 to 70° – as shown in Figure 3 – have to be provided for butt welds.


Figure 3 – Edge preparations for welding nickel alloys

and special stainless steels

Cleaning

Cleaning of the base material in the seam area (both sides) and the welding filler (e.g. welding rod) should be carried out

using acetone.

Welding filler

As welding fillers, VDM® FM 59 (preferred) or VDM® FM 625 are recommended:

VDM® FM 59 (mat. no. 2.4607)

ISO 18274 - S Ni 6059 (NiCr23Mo16), AWS A5.14 ERNiCrMo-13

VDM® FM 625 (W.-no. 2.4831)

ISO 18274 - S Ni 6625 (NiCr22Mo9Nb), AWS A5.14 ERNiCrMo-3

The use of bar electrodes in sleeves is possible.


Welding parameters and influences

It must be ensured that work is carried out using targeted heat application and low heat input as listed in Table 7 as an

example. The stringer bead technique is recommended. The interpass temperature should not exceed 120°C. In principle,

checking of welding parameters is necessary and it is therefore required to observe the section energy that is suitable for

the material.

The section energy E can be calculated as follows:

E = U x I x 60 /v x 1000 (kJ/cm)

U = arc voltage, volts

I = welding current strength, amperes

v = welding speed, cm/minute

Post-treatment

If the work is performed optimally, brushing immediately after welding, i.e. while still warm, and without additional pickling,

will result in the desired surface condition. In other words, heat tint can be removed completely. Pickling, if required or

specified, should generally be the last operation in the welding process. The information contained in the section entitled

"Descaling and pickling" must be observed. Heat treatments are normally not required before or after welding.


Thickness Welding

process

Filler material Rootpass1) Intermediate and final

passes

Welding

speed

Shielding gas

mm (in) Diameter

mm (in)

Speed

(m/min.)

I in (A) U in (V) I in (A) U in (V) (cm/min.) Type Rate

(l/min.)

1

(0.118)

Manual TIG 1.6-2.0

(0.063-

0.079)

90 10 110-120 11 10-15 I1, R1 (max

3% H2)

8-10

6

(0.236)

Manual TIG 2.0-2.4

(0.079-

0.094)

100-110 10 120-130 12 10-15 I1, R1 (max

3% H2

8-10

8

(0.315)

Manual TIG 2.4-3.2

(0.094-

0.126)

110-120 11 130-140 12 10-15 I1, R1 (max

3% H2

8-10

10

(0.394)

Manual TIG 2.4-3.2

(0.094-

0.126)

110-120 11 130-140 12 10-15 I1, R1 (max

3% H2

8-10

3

(0.118)

autom.

TIG2)

0.8

(0.0315)

0.5 140-160 10 25 I1, R1 (max

3% H2

15-20

5

(0.197)

autom.

TIG2)

0.8

(0.031)

0.5 140-160 10 25 I1, R1 (max

3% H2

15-20

2

(0.0787)

Autom. TIG

HD

1.0

(0.039)

0.3 180 10 80 I1, R1 (max

3% H2

15-20

10

(0.394)

Autom. TIG

HD

1.2

(0.042)

0.45 250 12 40 I1, R1 (max

3% H2

15-20

4

(0.157)

Plasma 0.8-1.0

(0.0315-

0.039)

0.5 165 25 25 I1, R1 (max

3% H2

30

6

(0.236)

Plasma 0.8-1.0

(0.0315-

0.039)

0.5 190-200 25 25 I1, R1 (max

3% H2

30

8

(0.135)

GMAW

(MIG/MAG)3

)

1.0

(0.039)

7-10 130-140 23-27 24-30 I1, R1 (max

3% H2, Z-

Gas with

max. 0,12%

CO2)

18-20

10

(0.394)

MIG/MAG3) 1.2

(0.047)

5-7 130-150 23-27 20-26 I1, R1 (max

3% H2, Z-

Gas with

max. 0,12%

CO2)

18-20

12

(0.472)

UP 1.6

(0.063)

240-280 28 45-55

20

(0.787)

UP 1.6

(0.063)

240-280 28 45-55

1) Root pass: it must be ensured that there is sufficient root protection, for example using Ar 4.6, for all inert gas welding processes.

2) Autom. TIG: the root pass should be welded manually (see manual TIG parameters)

3) GMAW (MIG/MAG): the use of multi-component shielding gases is recommended for MAG welding (CO2 < 0.12%).

Max. section energy kJ/cm: TIG, GMAW manual or automated, PAW (Plasma), SAW ca. 8 to 11.

The values are intended as guidance to simplify the setting of welding machines.

Table 7 – Welding parameters


Availability

VDM® Alloy 926 is available in the following standard semi-finished forms:

Sheet/Plate

Delivery condition: hot or cold rolled, heat treated, descaled or pickled

Condition Thickness

mm (in)

Width

mm (in)

Length

mm (in)

Piece Weight

kg (lb)

Cold rolled 1-7 (0.039-0.275) ≤ 2,500 (98.42) ≤ 12,500 (492)

Hot rolled* 3-60 (0.118-2.36) ≤ 2,500 (98.42) ≤ 12,500 (492) ≤ 1,700 (3,750)

Strip

Delivery condition: cold rolled, heat treated, pickled or bright annealed

Thickness

mm (in)

Width

mm (in)

Coil-insidediameter

mm (in)

0.025-0.15

(0.000984-0.00591)

4-230

(0.157-9.06)

300

(11.8)

400

(15.7)

500

(19.7)

–

0.15-2.5

(0.00591-0.0098)

4-720

(0.157-28.3)

300

(11.8)

400

(15.7)

500

(19.7)

–

0.25-0.6

(0.00984-0.0236)

6-750

(0.236-29.5)

– 400

(15.7)

500

(19.7)

600

(23.6)

0.6-1

(0.0236 -0.0394)

8-750

(0.315-29.5)

– 400

(15.7)

500

(19.7)

600

(23.6)

1-2

(0.0394-0.0787)

15-750

(0.591-29.5)

– 400

(15.7)

500

(19.7)

600

(23.6)

2-3

(0.0787-0.118)

25-750

(0.984-29.5)

– 400

(15.7)

500

(19.7)

600

(23.6)

Rolled sheet – separated from the coil – are available in lengths from 250-4,000 mm (9.84 to 157.48 in).

Rod

Delivery condition: forged, rolled, drawn, heat treated, oxidized, descaled or pickled, turned, peeled, ground or polished

Dimensions Outside diameter

mm (in)

Length

mm (in)

General 6-800 (0.236-31.5) 1,500-12,000 (59.1 – 472)

Material specific dimensions 10-400 (0.394-15.7) 1,500-12,000 (59.1 – 472)

Wire

Delivery condition: drawn bright, ¼ hard to hard, bright annealed in rings, containers, on spools and headstocks

Drawn

mm (in)

Hot rolled

Mm (in)

0.16 – 10 (0.0063-0.394) 5.5 – 19 (0.22-0.75)

Other dimensions and shapes such as discs, rings, seamless or longitudinally welded pipes and forgings can be

requested.


Publications

The following technical literature has been published about the material VDM® Alloy 926: Manfred B. Rockel, Wilfried R. Herda: “Die Oberflächenbehandlung von Schweißverbindungen hochkorrosionsbeständi-ger 6% Mo-Stähle und Nickel- Basislegierungen” [Surface Treatment of Weld Connections of Highly Corrosion Resistant 6% Mo Steels and Nickel Base Alloys], in WuK, issue 7, July 1992. Manfred B. Rockel, Wilfried R. Herda: “Zwei neue hochlegierte austenitische Sonderstähle mit höherem Molybdängehalt und Stickstoffzusätzen” [Two New High Alloyed Austenitic Special Steels with Higher Molybdenum Concentration and Nitrogen Additions], in STAHL ’92, issue 1, March 1992. E. Altpeter, U. Heubner, M. B. Rockel: “Potential-Sonden-Messungen und Potential-Profile über Schweißverbindungen korrosionsbeständiger Nickel- Basis-Werkstoffe und Sonderstähle” [Potential Probe Measurements and Potential Profi-les via Weld Connections of Corrosion Resistant Nickel Base Materials and Special Steels], in WuK, issue 3, March 1992. G. K. Grossmann, M. B. Rockel: “Use of high alloy materials under dewpoint corrosion conditions in waste incineration”, in METALL, issue 9, September 1991. Wilfried R. Herda, Dr. Manfred B. Rockel: “Anwendungsentwicklung für Nickelbasislegierungen auf dem Gebiete der Umwelttechnik” [Application Development for Nickel Base Alloys in the Field of Environmental Engineering] in METALL, issue 10, 1990, p. 984. Wilfried R. Herda, Manfred B. Rockel: “Nickelhaltige Legierungen und Sonderedelstähle in der Verfahrenstechnik” [Al-loys Containing Nickel and Special Stainless Steels in Process Engineering] Chem.-Ing.-Tech. 62, 1990, No. 4, pp. 299-303. R. Pleschko, R. Schimböck, E. M. Horn, P. Mattern, M. Renner und W. Heimann: “Walzplattierungen mit dem hochkor-rosionsbeständigen nichtrostenden austenitischen Stahl X1NiCrMoCuN25 20 6, W.-Nr. 1.4529” [Roll Cladding with the Highly Corrosion Resistant Austenitic Stainless Steel X1NiCrMoCuN25 20 6, Material no. 1.4529] WuK, issue 41, 1990, pp. 563-570. U. Heubner, M. B. Rockel, E. Wallis: “Das Ausscheidungsverhalten von hochlegierten austenitischen Stählen mit 6% Molybdän und sein Einfluß auf die Korrosionsbeständigket” [The Precipitation Behavior of High Alloyed Austenitic Steels with 6% Molybdenum and its Effect on Corrosion Resistance], WuK 40, 1989, pp. 459–466. Dr. M. B. Rockel: “Korrosionsbeständigkeit von Schweißverbindungen hochlegierter Werkstoffe” [Corrosion resistance of Weld Connections with High Alloyed Materials] in METALL, issue 4, 42th year, 1988, p. 338. H. Decking, W. R. Herda, M. Köhler: “Hochlegierte austenitische Sonderedelstähle für den Tunnelbau und tragende Bauteile: Superaustenite mit 6-7% Molybdän” [High Alloy Austenitic Special Stainless Steels for Tunnel Construction and Load-Bearing Components: super austenite with 6-7% molybdenum], Korrosionstagung, Pratteln, 1998.


12 September 2017

Publisher

VDM Metals International GmbH

Plettenberger Straße 2

58791 Werdohl

Germany

Disclaimer

All information contained in this data sheet is based on the results of research and development work carried out by VDM

Metals International GmbH and the data contained in the specifications and standards listed available at the time of print-

ing. The information does not represent a guarantee of specific properties. VDM Metals reserves the right to change

information without notice. All information contained in this data sheet is compiled to the best of our knowledge and is

provided without liability. Deliveries and services are subject exclusively to the relevant contractual conditions and the

General Terms and Conditions issued by VDM Metals. Use of the most up-to-date version of this data sheet is the re-

sponsibility of the customer.

Imprint

VDM Metals International GmbH

Plettenberger Straße 2

58791 Werdohl

Germany

Phone +49 (0)2392 55 0

Fax +49 (0)2392 55 22 17

[email protected]

www.vdm-metals.com

VDM Alloy 926 Cronifer 1925 hMo - VDM Metals | Home · PDF fileEN 1.4529 X1 NiCrMoCuN25-20-7...

Documents

Transcript of VDM Alloy 926 Cronifer 1925 hMo - VDM Metals | Home · PDF fileEN 1.4529 X1 NiCrMoCuN25-20-7...